Fuel processing systems include a fuel processor, or hydrogen-generating assembly, which produces hydrogen gas, and a fuel cell stack, which produces an electric current and water from the hydrogen gas and air. Because fuel cells are extremely sensitive to certain contaminants, care is taken to prevent the hydrogen feed to the fuel cell stack from containing more then acceptable levels of these contaminants. Therefore there is a need to detect contaminants in the product hydrogen stream from a fuel processor before the contaminated product stream reaches the fuel cell stack.
The present invention provides a system and method for detecting impurities in a hydrogen fuel stream for a fuel cell stack in sufficient time to prevent the impurities from reaching the fuel cell stack. In some embodiments, the hydrogen fuel stream is produced by a fuel processing assembly that is associated with the fuel cell stack. In some embodiments, the system or method are adapted to detect the concentration of a component that itself is not harmful to the fuel cell stack, or which is not harmful in an associated threshold concentration. In some embodiments, the detected composition is at least one of water, methane, and carbon dioxide.
Many other features of the present invention will become manifest to those versed in the art upon making reference to the detailed description which follows and the accompanying sheets of drawings in which preferred embodiments incorporating the principles of this invention are disclosed as illustrative examples only.